86 lines
2.3 KiB
C#
86 lines
2.3 KiB
C#
//------------------------------------------------------------
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//------------------------------------------------------------
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namespace System.Runtime
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{
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using System.Collections.Generic;
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class DuplicateDetector<T>
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where T : class
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{
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LinkedList<T> fifoList;
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Dictionary<T, LinkedListNode<T>> items;
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int capacity;
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object thisLock;
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public DuplicateDetector(int capacity)
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{
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Fx.Assert(capacity >= 0, "The capacity parameter must be a positive value.");
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this.capacity = capacity;
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this.items = new Dictionary<T, LinkedListNode<T>>();
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this.fifoList = new LinkedList<T>();
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this.thisLock = new object();
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}
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public bool AddIfNotDuplicate(T value)
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{
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Fx.Assert(value != null, "The value must be non null.");
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bool success = false;
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lock (this.thisLock)
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{
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if (!this.items.ContainsKey(value))
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{
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Add(value);
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success = true;
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}
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}
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return success;
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}
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void Add(T value)
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{
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Fx.Assert(this.items.Count == this.fifoList.Count, "The items and fifoList must be synchronized.");
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if (this.items.Count == this.capacity)
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{
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LinkedListNode<T> node = this.fifoList.Last;
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this.items.Remove(node.Value);
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this.fifoList.Remove(node);
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}
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this.items.Add(value, this.fifoList.AddFirst(value));
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}
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public bool Remove(T value)
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{
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Fx.Assert(value != null, "The value must be non null.");
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bool success = false;
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LinkedListNode<T> node;
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lock (this.thisLock)
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{
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if (this.items.TryGetValue(value, out node))
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{
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this.items.Remove(value);
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this.fifoList.Remove(node);
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success = true;
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}
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}
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return success;
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}
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public void Clear()
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{
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lock (this.thisLock)
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{
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this.fifoList.Clear();
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this.items.Clear();
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}
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}
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}
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}
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